1. Field of the Invention.
This invention relates to envelopes and in particular to a two-way envelope adapted for use with automatic mail processing equipment.
2. Description of the prior art.
Two-way or returnable mailing envelopes are widely used for business transactions where a reply to an initial mailing is required. For example, many businesses send their statements in two-way envelopes which their customers use for returning payments. An exemplary two-way envelope is shown in the Hiersteiner U.S. Pat. No. 3,152,751 and includes a flap which is divided by a tear line into an initial seal flap portion and a return flap portion. Upon receipt by the initial addressee, the initial seal flap portion is detached from the envelope and the return flap portion is utilized to seal the envelope pocket for a return trip. Return addresses and postage may be applied to the flap.
Another type of two-way envelope is shown in the Hiersteiner U.S. Pat. No. 4,180,168 and includes a pair of side flaps folded over a front panel to form a pocket. The side flaps have upper portions which form a return flap for sealing the pocket for a return mailing. An initial seal flap is integral with the front panel and demarcated therefrom by a tear line. The initial seal flap is folded over the return flap for an initial mailing and is detached from the envelope by the initial addressee.
However, the U.S. Postal Service has begun using automation equipment designed to apply and read zip codes in bar format which renders many such prior art two-way envelopes obsolete. Included in the automation equipment presently in use by the U.S. Postal Service are optical character readers which read zip codes and print them in bar format on mail pieces which do not already include bar format zip codes. Bar code readers are provided for processing mail with zip codes in bar format.
For two-way mailings, the initial address including a bar format code is preferably printed on materials enclosed in the envelope and visible through a window on the front panel thereof. It is likewise desirable for a return address on a two-way envelope to include a pre-printed zip code in bar format. Furthermore, facing identification marks which identify a return mailing as courtesy reply or business reply may be required to be printed on the outside of the envelope in its return configuration for detection by the Postal Service's automatic sorting equipment.
Many prior art two-way envelopes are unsuitable for use with such automation equipment because, in their return configurations, the initial address bar code may be visible through a window opening or elsewhere on the envelope if, for example, the initial recipient fails to remove the materials with his or her address prior to a return mailing. The initial bar format zip code may then be detected by a bar code reader, routed to the initial address rather than the return address and thus be prevented from completing its round trip. In fact, a "ping-pong" effect may result with the mail piece going back and forth between the postal system and the initial addressee without ever returning to the initial sender. Such mail pieces may ultimately be lost or at least delayed in reaching their intended destinations.
A related problem occurs if a facing identification mark appropriate only to the return trip is visible during the initial trip and is detected by an optical code reader. Also, many prior art two-way envelopes did not provide sufficient space for printing a return address with a zip code in bar format and the aforementioned facing identification marks.
The aforementioned problems may occur even with two-way mailings which are presorted to carrier routes for a first mailing. Although automatic processing equipment is thus avoided for an initial mailing, it may be encountered during a return mailing. If incorrect bar format zip codes or inappropriate facing identification marks are present, they may be detected by optical character readers or bar code readers and the mail pieces may be lost or delayed from reaching their destinations. Heretofore, there has not been available a two-way envelope particularly compatible with the Postal Service's automatic mail processing equipment with the features and advantages of the present invention.